1. Technical Field
The present invention relates to electronic devices and more particularly to devices and fabrication methods with self-aligned active regions.
2. Description of the Related Art
The semiconductor industry has been able to improve the performance of electronic systems by making ever-smaller devices. However, this approach has encountered technical limits giving rise to alternative device designs and technologies. One technology includes the use of carbon nanotubes (CNT) and, more recently, graphene layers and nanoribbons. Field-effect transistors based on semiconductor nanotubes and graphene nanoribbons may be used as high-performance devices.
The fabrication field-effect transistors may include a single-wall carbon nanotube connected to two metal electrodes. By applying a voltage to a gate electrode, the nanotube can be switched from a conducting to an insulating state. However, carbon based transistor devices often suffer from adhesion issues between carbon material and high dielectric constant (high-k) insulation materials. This is of particular concern in the formation of gate structures that often include both carbon conductors and the high-k materials. In addition, transistor designs suffer from alignment issues, which act as a barrier to reducing node sizes for future designs.